Patent US 4,520,274

An apparatus for controlling loads of a plurality of units on a shared source which includes a timer interfaced with a computer controlling the connection of each individual unit to the source on an individual basis for a connection period. The timer controls the connection and disconnection of each unit from the source for connection and disconnection periods. Sensors exist on each unit, each sensor having an output while registering differences between a nominal value of an operating parameter of the sensor's unit and an actual value of the operating parameter. The computer compares over time each sensors output to determine an adjustment value of the approximate relative difference over time between the nominal value of the unit's operating parameter and the actual value of the unit's operating parameter. The computer adjusts the timer to compensate for each unit's relative length of disconnection period to the length of connection period in proportion to the adjustment value of the unit. The computer can also reset the timer to sequentially repeat the controlling, connecting, and disconnecting of the units to the source.